Fermentation of cellulose



?atentecl Aug... 16, 192?.

unfi STATE-S HERBERT Lancwjnnr, or EPSOM, ENGLAND.

' FERMENTATIO-N F CELLULOSE.

No Drawing. Application filed January- 7, 1921, Serial 1N0. 435,734, and in Great Britain January 8, 1820."

This invention relates to themanufacture of products obtained by the direct fermentation of cellulose and is an improvement of the process described in the specification of 5 my United States Patent no. 1,443,881,

dated 30th January, 1923.

In the specification of said patent, I have described and claimed a process for the direct fermentation of cellulose with the object of obtaining certain valuable products, such as acetic acid and other fatty acids, and organic compounds, characterized by the combination of certain conditionsin carrying out said process.

One element of said combination is that the fermentation process should be carried out under aerobic conditions. c

Further investigations have shown that when aeration is complete, that is to say, when aerobiosis occurs in the highest degree possible in the normal atmosphere, the fer nientation is slow, and that the degree of aeration of the culture has a considerable effect, as a matter of fact, a greater effect on the course of the fermentation and the products obtained thereby than was at first anticipated.

I have now studied the conditions of aeration by varying the degree of aeration of the culture, and have examined the products obtainedthe reby. I have found that when the aeration is highly limited acetic acid is the main useful product, so that the best yieldof acetic acid may be obtained under such conditionsof limited aeration.

On the other hand, I have found as' the aeration is increased, the lighter fatty alcohols, particularly ethyl alcohol, are pro duced, until under complete aerobiosislethyl alcohol is the main useful product, although asalready, stated, the fermentation is slow under these conditions. T

Thus the fermentation can be so controlled by suitable regulation of aeration, to produce the best yield of acetic acid as] the main product or the best yield of alcohol as the main product,.generally speaking the lower degree of aeration being the conditions for the best yield of acetic acid or the like, whereas, by suitably increasing the aeration the best yield of alcohol may bevobtained.

I have further found that under suitable conditions another element of the combination of the conditions set forth in the specification ofmy Patent No. 1,443,881 for-obtainingthe best results of fermentation 'of cellulose, i. e., the addition of the more soluble and easily fermentable carbohydrates acting as a primer to the fermentation, may be dispensed with.

The present invention consists in carryin out the process of direct fermentation of cellulose, as set forth in the specification of my Patent No. 1,443,881, by regulating the degree of aeration of the culture with the ob ect of influencing the products obtained thereby.

In carrying out the process, the conditions set forth in the specification of my aforesaid Patent No. 1,443,881 should be observed, and in case it is required to produce lighter aliphatic alcohols or ethyl alcohol,

the aeration should be increased to such a degree that these alcohols are formed, which M39571 'JPATENTYOFEFICE.

can be easily ascertainedloy examining samples of the mass under treatment at; various v stages of the process.

The alcohol formed should be removed from the culture as far as possible as soon as, it is produced or at the rate at which it is produced, in other words, the "concentration of the alcohol should be maintained in such a way that thefermentatio'n' is not adversely affected thereby. This may be effect'ed for example by distillation in a partial vacuum at temperatures up to, for 'ex ample, 60 C.

In carrying out the invention for the production of acetic acid or similar fatty acids, similar conditions to those set forth in the specification of my Patent No. 1,443,881

should be observed, and the aeration of the culture should be limited to such a degree that mainly acetic acid or other fatty acids are produced. The control of the aeration can be easily efiected by examining samples of the mass under treatment at various stages of the process. 1 j

As previously stated, in "either case, whether there her'increased aeration or re-' stricted aeration, the addition of priming. substances, such asthe more solubleand easily fermentable carbohydrates may be What I' claim as new and desireto secure Y dispensed with.

by Letters Patent is 1. The process of obtaining alcohol which comprises preparing a 'mash-fof cellulose-1f containing material, inoculating-said mash,

with an organism which is. adapted to attack cellulose and thereby to produce ethyl" alcohol and aliphatic acids, allowing said alcohol and aliphatic acids, allowing said mash to ferment with aeration and increasmash to ferment with aeration, increasin ing the de ree of aeration above that at the degree of aeration above that at whic which main aliphatic acids are formed, unmainly aliphatic acids are formed, in order 8 til mainly et yl alcohol is produced. to produce mainly ethyl alcohol, and mainl5 2. The process of obtaimn alcohol which taining the alcohol formed at a concentration comprises preparing a mas of cellulosenot substantially interfering with the fer-- containing material, inoculating said mash mentation. with an organism which is adapted to at- In testimony whereof, I afiix my si nature. 10 tack cellulose and thereby to produce ethyl HERBERT LANGW LL. 

